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    <title>Document</title>
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    <script>
        function getSum () {
            var sum = 0;
            for (var i = 0; i < arguments.length; i++) {
                var subArr = arguments[i]; // [1, 2, 3, 4]
                for (var j = 0; j < subArr.length; j++) {
                    sum += subArr[j];
                }
            }
            return sum;
        }
        console.log(getSum([1, 2, 3, 4],[5, 6, 7]));
    </script>
</body>
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